AUDIE CORNISH, HOST:
The number of pedestrians and cyclists dying on the nation's roadways is rising. That's according to the National Highway Traffic Safety Administration. The two biggest cities - New York and Los Angeles - have the highest rates of those deaths. Gloria Hillard has more from L.A.
GLORIA HILLARD, BYLINE: The flowers of this makeshift memorial along a busy street in south Los Angeles are wilting within a jagged circle of candles. A stuffed animal leans against a cardboard cross, and taped to poster board are family pictures of the disabled teen killed while crossing the street by a hit-and-run driver.
UNIDENTIFIED MAN #1: Roger 102 (unintelligible).
OFFICER CAROL MITCHELL: After he was struck, the vehicle slowed down momentarily and then proceeded south and never stopped, never came back.
HILLARD: Los Angeles police officer Carol Mitchell is the lead officer on the case.
MITCHELL: As long as I've, you know, been doing it, it still doesn't, you know, get easier. I mean, each one of these fatalities affects me.
HILLARD: The only clues available to investigators are the blurred, black-and-white images captured by a nearby business surveillance camera. They cannot identify the driver of the minivan or the license plate. On this day, Mitchell and her partner will spend hours canvassing the boulevard.
MITCHELL: There are more cameras here we're going to look at.
HILLARD: These cases can go cold very quickly. As with most crimes, the first 48 hours are crucial.
MITCHELL: This was at 7 p.m. Somebody saw this happen. And if they didn't see it, they have seen a car that fits that description with, you know, that traffic collision damage to it, and they're just not saying anything. People just don't want to get involved.
HILLARD: Mitchell's next stop is a body shop. Hit-and-run drivers will often try to repair collision damages or paint the vehicle another color.
MITCHELL: No vans have been brought here? Blue vans or green vans?
UNIDENTIFIED MAN #2: No.
POLICE OFFICER CAROL MITCHELL: Let me tell you, I'm going to take a look in here.
UNIDENTIFIED MAN #3: In here? OK.
HILLARD: In 2012, LAPD recorded more than 2,500 so-called motor vehicle versus pedestrian incidents. They range from minor injury to death. A study by the University of Michigan Transportation Research Institute found that pedestrian traffic fatalities in Los Angeles are nearly triple the national average.
DETECTIVE BILL BUSTOS: Just in the last few days, we had three pedestrians who were just killed when they were crossing the street.
HILLARD: Detective Bill Bustos is officer in charge of LAPD's Valley Traffic Division. He says, like many cities across the country, L.A. drivers and pedestrians are increasingly distracted by electronic devices. But here, the problem is even worse.
BUSTOS: Here, we live in our vehicle practically. We commute everywhere we go.
OFFICER RHIANNON TALLEY: William 53, I'm code 6 with 50.
HILLARD: LAPD Officer Rhiannon Talley and her partner, Detective Chris Laurino, have huge caseloads.
TALLEY: There's just so much, so many cases, so many victims and not enough hours in the day.
DETECTIVE CHRIS LAURINO: We handle as much if not more fatalities than most homicide units.
HILLARD: Arriving at a scene of a serious accident involving a pedestrian is not for the faint of heart. But one of the hardest things for investigators to deal with, Laurino says, is when the person responsible for the carnage has left the scene.
LAURINO: They'll drive their car home, and they'll wash the blood off, cover the car up and act like nothing happened. It's incredible the lack of conscience some people have.
HILLARD: This year, the Valley Traffic has solved roughly half of its pedestrian hit-and-run fatalities. Captain Jeff Bert.
CAPTAIN JEFF BERT: When there's a hit and run, unlike other crimes, the evidence, the primary evidence is gone, and what you're left with, if you look at a fatality, is a body. But I can imagine for families, for loved ones, for people that have lost the most precious thing in their life and then to have a department not be able to solve it, it must be maddening.
JERI DYE LYNCH: Anytime I go back to that day, it's a hard one.
HILLARD: Two years ago, Jeri Dye Lynch's 16-year-old son, Conor, was crossing a street near his school when he was struck and killed by a driver in an SUV.
LYNCH: In Conor's case, there were some great Samaritans, and it really, you know, that's that one thing that gives me a lot of comfort to know that he wasn't just there, you know, a 16-year-old on the street just dying with nobody there because the driver left.
HILLARD: Lynch says the 18-year-old unlicensed driver ended up turning herself in.
LYNCH: She plea-bargained, and her sentence was probably by any measure a slap on the wrist.
HILLARD: According to Lynch, the driver received 90 days community service and three years' probation. Even today, on the street where Conor was hit, few if any of the drivers pay attention to the posted school zone speed of 25 miles an hour or the hand-painted murals and fresh flowers of what is now the teen's permanent memorial. For NPR News, I'm Gloria Hillard.